Last week's press conference with Musk holding his son on his shoulders whilst standing over a seated Trump made a very interesting photo.Trump no doubt would have hated that as he looked the subordinate.
Yesterday's press conference was very different with Musk being deferential to Trump on one hand , but also blaming him for the email to the federal workers; " He told me to be more aggressive .... So I said ok ...yes sir, he's the president." He was trying to minimise the email and said they were just trying to get rid of people from the payroll who aren't doing a good job. How he thought his crass email would do that wasn't clear.
I give that relationship 6 months. Two massive egos like that will clash.